src/libsdl/sdl.c

   1 /* SDL handling
   2  *
   3  * (C) 2018 by Andreas Eversberg <jolly@eversberg.eu>
   4  * All Rights Reserved
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdint.h>
  22 #include <errno.h>
  23 #include "print.h"
  24 #include "sdl.h"
  25 #include "opengl.h"
  26
  27 #define GL3_PROTOTYPES 1
  28 #include <GL/glew.h>
  29
  30 static int sdl_initialized = 0;
  31 static int audio_initialized = 0;
  32 static SDL_Window *gl_window = NULL;
  33 static SDL_GLContext gl_context = NULL;
  34 static void (*keyboard_sdl)(int down, SDL_Keycode sym) = NULL;
  35 static void (*audio_sdl)(float *data, int len) = NULL;
  36
  37 static void audio_cb(void __attribute__((unused)) *userdata, Uint8 *stream, int len)
  38 {
  39         float audio_data[len / sizeof(float)];
  40
  41         SDL_memset(stream, 0, len);
  42         audio_sdl(audio_data, len / sizeof(float) / 2);
  43         SDL_MixAudio(stream, (Uint8 *)audio_data, len, SDL_MIX_MAXVOLUME);
  44 }
  45
  46 int init_sdl(const char *progname, int width, int height, int sound_samplerate, int sound_chunk, void (*keyboard)(int down, SDL_Keycode sym), void (*audio)(float *data, int len), int multisampling)
  47 {
  48         int rc;
  49
  50         keyboard_sdl = keyboard;
  51         audio_sdl = audio;
  52
  53         /* init SDL library */
  54         rc = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO);
  55         if (rc < 0) {
  56                 print_error("Failed to init SDL\n");
  57                 goto error;
  58         }
  59         sdl_initialized = 1;
  60
  61         if (multisampling) {
  62                 SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
  63                 SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
  64                 SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
  65                 SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
  66                 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
  67                 SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
  68                 SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, multisampling);
  69         }
  70
  71         /* open window */
  72         gl_window = SDL_CreateWindow(progname, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
  73         if (!gl_window) {
  74                 print_error("Failed to open SDL window: %s\n", SDL_GetError());
  75                 rc = EIO;
  76                 goto error;
  77         }
  78
  79         /* create GL context */
  80         gl_context = SDL_GL_CreateContext(gl_window);
  81         if (!gl_context) {
  82                 print_error("Failed to create SDL's OpenGL context: %s\n", SDL_GetError());
  83                 rc = EIO;
  84                 goto error;
  85         }
  86
  87         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
  88         if (rc < 0) {
  89                 print_error("Failed to set SDL's OpenGL context profile\n");
  90                 goto error;
  91         }
  92
  93         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
  94         if (rc < 0) {
  95                 print_error("Failed to set SDL's OpenGL major version\n");
  96                 goto error;
  97         }
  98         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
  99         if (rc < 0) {
 100                 print_error("Failed to set SDL's OpenGL minor version\n");
 101                 goto error;
 102         }
 103
 104         rc = SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 105         if (rc < 0) {
 106                 print_error("Failed to set SDL's OpenGL doublebuffer\n");
 107                 goto error;
 108         }
 109
 110         rc = SDL_GL_SetSwapInterval(1);
 111         if (rc < 0) {
 112                 print_error("Failed to set SDL's OpenGL swap interval to VBLANK\n");
 113                 goto error;
 114         }
 115
 116 #ifndef __APPLE__
 117         glewExperimental = GL_TRUE;
 118         if (glewInit() != GLEW_OK) {
 119                 print_error("Failed to init GLEW\n");
 120                 goto error;
 121         }
 122 #endif
 123
 124         /* just in case */
 125         glDisable(GL_DEPTH_TEST);
 126         glDisable(GL_CULL_FACE);
 127         if (multisampling)
 128                 glEnable(GL_MULTISAMPLE);
 129
 130         /* open audio */
 131         SDL_AudioSpec want, have;
 132         SDL_memset(&want, 0, sizeof(want)); /* or SDL_zero(want) */
 133         want.freq = sound_samplerate;
 134         want.format = AUDIO_F32; /* we always use float in this project */
 135         want.channels = 2;
 136         want.samples = sound_chunk; /* must be a power of two */
 137         want.callback = audio_cb;
 138         rc = SDL_OpenAudio(&want, &have);
 139         if (rc < 0) {
 140                 print_error("Failed to open audio\n");
 141                 goto error;
 142         } else if (have.format != want.format) {
 143                 print_error("Failed to open audio with desired audio format\n");
 144                 SDL_CloseAudio();
 145                 rc = -EIO;
 146                 goto error;
 147         } else if (have.freq != want.freq) {
 148                 print_error("Failed to open audio with desired sample rate\n");
 149                 SDL_CloseAudio();
 150                 rc = -EIO;
 151                 goto error;
 152         } else if (have.channels != want.channels) {
 153                 print_error("Failed to open audio with desired channels (got %d)\n", have.channels);
 154                 SDL_CloseAudio();
 155                 rc = -EIO;
 156                 goto error;
 157         } else {
 158                 SDL_PauseAudio(0);
 159                 audio_initialized = 1;
 160         }
 161
 162         return 0;
 163
 164 error:
 165         exit_sdl();
 166         return rc;
 167 }
 168
 169 static int key_ctrl = 0, fullscreen = 0;
 170
 171 int event_sdl(void)
 172 {
 173         int quit = 0;
 174         SDL_Event event;
 175
 176         while (SDL_PollEvent(&event)) {
 177                 if (event.type == SDL_QUIT)
 178                         quit = 1;
 179                 if (event.type == SDL_WINDOWEVENT) {
 180                         if (event.window.event == SDL_WINDOWEVENT_SIZE_CHANGED)
 181                                 resize_opengl(event.window.data1, event.window.data2);
 182                 }
 183                 if (event.type == SDL_KEYDOWN) {
 184                         switch (event.key.keysym.sym) {
 185                         case SDLK_f:
 186                                 if (key_ctrl) {
 187                                         if (fullscreen) {
 188                                                 fullscreen = 0;
 189                                                 SDL_SetWindowFullscreen(gl_window, 0);
 190                                                 SDL_ShowCursor(SDL_ENABLE);
 191                                         } else {
 192                                                 SDL_SetWindowFullscreen(gl_window, SDL_WINDOW_FULLSCREEN_DESKTOP);
 193                                                 SDL_ShowCursor(SDL_DISABLE);
 194                                                 fullscreen = 1;
 195                                         }
 196                                 }
 197                                 break;
 198                         case SDLK_LCTRL:
 199                         case SDLK_RCTRL:
 200                                 key_ctrl = 1;
 201                                 break;
 202                         }
 203                         keyboard_sdl(1, event.key.keysym.sym);
 204                 }
 205                 if (event.type == SDL_KEYUP) {
 206                         switch (event.key.keysym.sym) {
 207                         case SDLK_LCTRL:
 208                         case SDLK_RCTRL:
 209                                 key_ctrl = 0;
 210                                 break;
 211                         }
 212                         keyboard_sdl(0, event.key.keysym.sym);
 213                 }
 214         }
 215
 216         return quit;
 217 }
 218
 219 void swap_sdl(void)
 220 {
 221         SDL_GL_SwapWindow(gl_window);
 222 }
 223
 224 void exit_sdl(void)
 225 {
 226         /* close window */
 227         if (gl_window) {
 228                 SDL_DestroyWindow(gl_window);
 229                 gl_window = NULL;
 230         }
 231
 232         /* clear OpenGL context */
 233         if (gl_context) {
 234                 SDL_GL_DeleteContext(gl_context);
 235                 gl_context = NULL;
 236         }
 237
 238         /* exit SDL library */
 239         if (audio_initialized) {
 240                 SDL_PauseAudio(1);
 241                 SDL_CloseAudio();
 242                 audio_initialized = 0;
 243         }
 244         if (sdl_initialized) {
 245                 SDL_Quit();
 246                 sdl_initialized = 0;
 247         }
 248 }
 249